Manufacturing solid products



Patented Nov. 6, 1945 U ITED S S PATENT orrlca rnonuors I allir Keller,St. Louis, Mo,, to Mom tion of Delaware St. Louis, Mo., a corpora-v N'oApplication February 15, 1943,

Serial No. 475,971

The present invention relates to synthetic materials having rubber-likephysical characteristics and more particularly to rubbery compositionsderived from thethermal reaction of ethyl cellulose withcertainsubstituted polyphenyl hydrocarbons, certain auxiliary resins andcertain hydrogenated fatty acid esters.

Elastomers, or "lastics" as they are otherwise termed, are defined inthe Condensed Chemical- Dictionary, Third Edition, 1942 (Rhinehold Pub-'lishing Corporation), P es 265 and 288, as new materials of syntheticorigin possessing outstande ing elasticity or rubberiness and preparedby a variety of'methods; for example, (1) by chemical reaction (2) bypolymerization, or (3) by formulation, By suitable treatment andchemical formulation', products of widely different charac-. teristicsmay be obtained, ranging from hard brit-' tle masses to soft elasticmasses. Elastomers possess, in general varying degrees of resistance todeterioration under conditions which cause natural rubber to failrapidly; for example, attack by gasoline, oils and lubricants, chemicalsolvents,

sunlight, ozone, atmospheric oxygen, heat and other agencies.

Various attempts have been made to'produce plastics by incorporating a,plasticizer, and in some instances a resin, with ethyl cellulose. Thematerials so produced were," in some cases, capable of being formed intopliable or flexible films, but were in no sense possessed of the rubberycharacteristics which distinguish elastomers from plastics. In otherwords, there is aplear distinction between a plastic and an elastomer;

The object of the present invention is to provide novel elastomersderived from ethyl cellulose and having utility as rubber substitutesfor many of the purposes for which rubber is used.

A further object is to provide novel elastomers having utility asextenders for synthetic rubbers.

A further object is to provide novel elastomer compositions havingutility as dipping agents and coating emulsions and particularly assubstituted for all or part of the rubber normally used in compositionsfor this purpose.

Another object is to provide aprocess for preparing the novel elastomersand elastomer compositions of this invention.

Fin-the;- objects will appear from the detailed description in whichwill be set forth a number of embodiments of this invention; it is to beunderstood, however, that this invention is susceptible of variousembodiments within the'scope of the appended claims.

The application embodying the present invention is acontinuation-in-part of my co-pendins drocarbon such as ortho, meta andpara diphenyl benzene, ortho, meta and para nitro diphenyi and others.An auxiliary resin such as a phenol aldehyde thermo-setting resin, 9.polycoumarone-indene resin or an alkyd resin may also be employed eitherin place of part of the polyphenyl hydrocarbon or in addition thereto. Ahydrogenated fatty acid ester is also desirably employed as aconstituent of the reaction mixture. a

The auxiliary resin serves to supplement or extend the function of thesubstituted polyphenyl hydrocarbon in the thermal reaction from whichthe elastomer emerges. The hydrogenated fatty acid ester also serves tosupplement the function of the substituted polyphenyl hydrocarbon.Likewise, in the employment of two or moresubstituted polyphenylhydrocarbons, the second and subsequent hydrocarbons may be consideredas supplementing or extending the function of the first hydrocarbon inthe reaction. The term "extender is employed hereinafter to designatethe resin or the additional substituted polyphenyl hydrocarbons employedin some instances in the practice of this invention. The use of anextender in this respect has the advantage of avoiding any substantialtendency for blooming or reversion to take place when the limits of thecompatibility of a selected substituted polyphenyl hydrocarbon areapproached. Likewise, as will be described hereinafter, the elastomersof the present invention may be employed to supplement or extend thevarious synthetic rubbers, and in this respect, the term "syntheticrubber extender is used hereinafter.

The mixture is heated in a suitable reaction vessel, for example, anoil-jacketed mixer, at reaction temperatures within the range of -240 C.and for a period of time ranging from 20 minutes to several hours orlonger. Under these conl ditions, the components of the reaction mixtureform a homogeneous viscous liquid which, upon cooling, becomes a rubberysolid.

It is a feature of the present invention that dipping mediums embodyingthe novel elastomers of the present invention can be prepared readily bydispersing the elastomer in an organic solvent such as benzene orxylene. It is further a feature of this invention that coating emulsionsembodying the novel elastomers of the present invention can be preparedreadily by stirring a hot solution of the elastomer in an organicsolvent containing an acidic emulsifying agent into an aqueous solutionof ammonia or an aqueous solution of a water soluble nitrogenous organicbase, such as morpholine, or reversing this order.

The novel elastomers of the present invention appear to be the result,to some extent at least,

of a'chemical reaction between the ethyl celluassaeis composition of thesubstituted polyphenyl hydrocarbon, hydrogen bonding and reactionthrough secondary valences are among the possible reactions takingplace.

Suitable types of ethyl cellulose for the purpose of this invention arethose having a viscosity in the range of 100-300 or higher, anddesirably in the vicinity of 300. Mixtures of two or more types of ethylcellulose having viscosities, for example, of 100 and 300 respectively,may be used.

The viscosity of the ethyl cellulose employed is determined by thefalling ball method on a 5% by weight solution in 80:20 toluene-ethanolsolvent at C. The absolute viscosity, expressed in centipoises, is usedto designate the viscosity types. r

Suitable polyphenyl hydrocarbon derivatives for the purpose of-thisinvention are solidcrystalline nitroor aryl-substituted polyphenylhydrocarbons, such as ortho, meta and para nitro diphenyl, ,4'- and2,4'-'dinitro diphenyls, ortho-, metaand para-diphenyl benzene andmixtures of the respective substituted polyphenyls.

Suitable auxiliary resins for the purpose of this invention are thephenol-aldehyde thermo-set-' ting resins, such as phenol-formaldehyderesins, phenol-butyraldehyde resins, o-cresol-formaldehyde resin,m-cresol acetaldehyde resin; oil-soluble resins, such as tertiary butylphenol-aldehyde resins, m p-eresol-benzaldehyde-acetaldehyde resin,phenol-acetylene-acetaldehyde r e s i n, methylene-diphenylamine-phenolresin; poly-- coumarone-indene resins; isomerized terpene resins; estergum, alwd resins, such as glycolphthalicanhydride-succinic acid resin,dihydroxy stearic acid-maleic acid resin, glycerine-adipic acid resin;and aryl sulfonamide-aldehyde resins, such as benzenesulfonamide-formaldehyde resin and oand p-toluenesulfonamide-formaldehyde resin.

Suitable hydrogenated fatty acid esters for the purpose of thisinvention are hydrogenated castor oil and hydrogenated glycerides ofoleic, stearic and 'palmitic acids. As. an alternative, anunhydrogenated fatty acid ester may be incorporated in the fatty acidmixture and hydrogen gas may thereupon be passed into the mixture.

Suitable acidic emulsifying agents for the purpose of this invention aredistilled linoleic and linolenic acids, stearic acid, 'oleic acid,ricinoleic acid and other higher fatty acids.

Suitable alkaline emulsifying agents for the purpose of this inventionare: ammonia, morpholine, 2-amino-2 methyl-l-propanol andtriethanolamine.

- The proportions of the respective components which are reacted to formthe novel elastomert the like.

of this invention may be varied over a wide range. It is not feasible toset a definite limit to. this range because the proportions of thecomponents depend upon the characteristics desired in the product andthe purpose for which the elastomer is intended. In general, the ratioof substituted polyphenol hydrocarbon to ethyl cellulose is desirablywithin the range of 0.4-2. Likewise, the ratio of auxiliary resin toethyl cellulose is desirably within the range 01 0-1.5. Also the rangeof hydrogenated higher fatty acid esters to ethyl cellulose is withinthe range of -1.0. The range of proportions of the components of thenovel elastomers and elastomer compositions of this invention will befurther illustrated in the examples which follow. These examples,however, are to j be construed merelyas illustrative and not aslimphenyl benzene are melted in an oil-jacketed mixer wand 45 parts byweight of ester gum are incorporated in the hot melt. The temperature israised gradually to 160 and parts by weight of ethyl cellulose having aviscosity of centipoises are incorporated in the .hot melt. Thetemperature of 160 C. is maintained for aperiod of 40 minutes. Themolten mass is then poured into a mold .or flowedonto a plateand cooled.The cooled product is uniform in structure, i'iexible and of theconsistency of a tough rubber. The elastomer thus formed may be workedon hot rolls to form sheet material or may be molded into variousshapes. such as washers, gaskets and Example II I One hundred twentyparts by weight of ortho diphenyl benzene having a viscosity oi. 300centipoises are melted on hot rolls and 45 parts by weight ofparacoumarone-indene resin. known to the trade as "Cumar"- resin, areincorporated in the hot melt on the rolls. The temperature of the rollsis then raised gradually so that the hot melt reaches a temperatureabove C. and preferably in the vicinity oi C; At this point, 80 parts byweight of ethyl cellulose is added to the hot melt and the reactionmixture is agitated on the rolls for a period of 25 minutes. The mass isthen cooled and shaped into desired forms. The elastomer of this exampleis pliable and flexible and resembles rubber in physical appearsince.The elastomer may be cold-worked on rolls to form sheet material whichis suitable for the preparation ofgaskets and washers.

Ewample III v P I Ethyl. celluloselviscosity 100 centipoises) 12 Mixturecontaining 95% ortho diphenyl benzene and 5% meta diphenyl benzene 20Ester gum 20 Hydrogenated castor oil 5 Mixture of linoleic and linolenicacids 0 minutes to emulsify the components, The emul- Example IV Theelastomer resulting from the reaction of the above materialsaccording'to the method of Example I was found to possess substantiallythe characteristics of the elastomer of Example VI.

The ester gum may be the material known to Grams the trade as ester gumB-L," a product ofAmer- Ethyl cellulose (viscosity loo centipoises')---a0 Cymamlde Ortho nitro diphenyl 120 Example VIII Estergum--- 80 GramsHydrogenated castor oil Ethyl cellulose (yiscosity 300 centipoises)---150 The reaction is conducted according to the method of Example I. Theresulting elastomer'is a tough, flexible rubbery material with a slighttack and no tendency to bloom, i. e. to exude crystals of an unreactedcomponent. The elastomer is useful as an extender for synthetic rubber.

The substitution of a phenol-aldehyde resin, such as phenol formaldehyderesin, for the ester gumrwhich is a resin derived from theesteriflcation of rosin and glycerine, resulted in a similar productcharacterized by the absence of tack.

Example V c Grams Ethyl cellulose (viscosity 100 centipoises) 80 Orthonitro diphenyl 120 Mixture of 95% meta diphenyl benzene and of a blendof ortho and para diphenyl benzene 40 Phenol-formaldehyde resin 120Hydrogenated castor oil Mixture of 95% meta diphenyl benzene andThe'reaction was conducted according to the-- method of Example 1., Theresulting elastomer was tough and possessed the characteristic of greatstability and absence of blooming over a long period of time.

The mixture of diphenyl benzenes may be the material known to the tradeas Santowax-M.-

The phenol formaldehyde resin may be the material known to the trade asDurez-219. The hydrogenated castor oil may be the material known to thetrade as Op Wax? Example VI Grams Ethyl cellulose (viscosity 300centipoises) 90 Ortho nitro diphenyl -i 20 Mixture of 95% meta diphenylbenzene and 5% of a blend of ortho andpara diphenyl benzenes Mixture of95% ortho diphenyl benzene and 5% of meta diphenyl benzene 30Hydrogenated castor oil 20 The elastomer resulting from the reaction ofthese materials according to the method of Example I was a hard, tough,rubber-like material suitable for the manufacture of heels for shoes,and similar articles in which rigidity and toughness combined withelasticity are necessary characteristics.

The mixture of 95% ortho diphenyl benzene and 5% meta diphenyl benzenemay be the material known to the trade as Santowax-O.

Example VII Grams Ethyl cellulose (viscosity 300 centipoises) Mixture of95% meta diphenyl benzene and 5% of a blend of ortho and para diphenylbenzene 120 70 Mixture of 95% ortho diphenyl benzeneand I 5% metadiphenyl benzene '10 Ortho nitro diphenyl 40 Ester gum 120 Hydrogenatedcastor oil 15 Mixture of ortho diphenyl benzene 5% of a blend of orthoand para diphenyl benzenes and 5% meta diphenyl benzene 60 Ortho nitrodiphenyl 40 Hydrogenated castor oil 15 The elastomer resulting from thereaction of the above materials according to the method of Example I wasfound to possess a higher softening point than the elastomer of ExampleVII.

benzenes 90 Mixture of 95% ortho diphenyl benzene and 5% meta diphenylbenzene 11'7 Ester gum 98 I-Lvdrogenated castor oil 25 The elastomerresulting from the reaction of these materials according to the methodof Example I was found to possess very desirable char acteristics as asubstitute for rubber where a rigid but elastic material is required.

' Example X Ethyl cellulose (viscosity 300 centipoises) Mixture of 95%ortho diphenyl benzene and 5% meta diphenyl benzene 210 Ester gum 90Hydrogenated castor oil 50 The elastomer resulting from the reaction ofthe above materials according to the method of Example I was found topossess excellent characteristics as a tough elastic material for thepreparation of gaskets, washers and tank linings where resistance tocorrosion and abrasion are encoun- The elastomer resulting from thereaction of these materials, according to the method of Example I,possessed the characteristics of the elastomer of Example X togetherwith an increased degree of hardness. The elastomer may be extended with15% to 20% of Gilsonite at a temperature of approximately 295 F., andthe resulting elastomer a relativel high degree oftoughness combinedwith sumcient elasticity to render the material highly useful for suchpurposes as conveyor belt linings,

Example XII Grams Ethyl cellulose (viscosity 100 centipoises) 150Mixture of 95% meta diphenyl benzene and 5% of a blend of ortho and paradiphenyl thus modified was stirred into a solution containing 3 gruns ofmorpholine and 35 grams of water and agitation was continued until anemulsion was formed. The emulsion of this example benrenes 100 Mixtureof 95% ortho diphenyl benzene anti 5% meta diphenyl benzene 130 Orthonitro diphenyl 30 Ester gum 60 Phenol formaldehyde resin 30 Hydrogenatedcastor oil 45 The elastomer was prepared according to the method ofExample I and the product was cast into the form of a slab and allowedto cool. The elastomer of this example was found to be a very stable,tough and elastic material suitable for many of the purposes for which arubber possessing similar characteristics is normally used.

The diphenyl benzenes, resin and hydrogenated castor oil are meltedtogether and .the temperature is raised to slightly higher than. 140 C.The

ethyl cellulose is thereupon incorporated and the temperature is raisedgradually to 180 C. and maintained at that point for at least 25minutes. The hot melt is thereupon poured or cast into suitable molds.The polycoumarone-indene resin employed in this instance may be thematerial known to the trade as Cumar MH-il. The elastomer of thisexample is hard and tough with a moderate degree of elasticity.

Example XIV Grams Ethyl cellulose (viscosity 100 centipoises)- 15Mixture of 95% ortho diphenyl benzene and 5% meta diphenyl benzeneIsomerlzed terpene resin (condensation product of dipentene with phenoland formaldehyde) Hydrogenated castor oil 7 The materials were reactedaccording to the method of Example 1. After the reaction was complete,10 grams of a mixture of linoleic and linolenlc acids and 100 cc. ofxylene were incorporated into the hot melt. The melt thus modiiied wasstirred into a solution of 9 grams of morpholine in 90 cc. of water andagitation was continued thereafter until an emulsion was formed. Theemulsion was found to be highly suitable for coating articles of paper,wood, leather and metal and the coatings thus provided were was found tobe suitable for coating purposes and particularly for metal articles.The film resulting when the emulsim was dried was found to be relativelyhard with a moderate degreeoi' elasticity.

Example XVI Grams Ethyl cellulose (viscosity 100 centipoises) 20 Mixtureof 95% ortho diphenyl benzene and 5% meta diphenyl benzene 18 Orthonitro diphenyl 5 Phenol-formaldehyde resin 35 Hydrogenated castor-oil 7This elastomer, prepared according to the method of Example I, wasdissolved in a benzene-xylene mixture in the ratio of 2 to 4 pounds pergallon of the solvent. The resulting solution was found to possess greatutility as a dipping medium formetal objects, such as magnesiumcastings, to provide protecting coatings on such objects.

Example XVII A Pounds Ethyl cellulose (viscosity 300 centipoises) 9.5Mixture of 95% ortho diphenyl benzene and 5% meta diphenyl benzene 13Phenol-aldehyde resin 13 Mixture of linoleic and linolenic acids 6.5Hydrogenated castor oil 1 Xylene 51.5 Water 62 Aqueous ammonia (28% NHa)1.5

, The diphenyl benzenes and the phenol-aldehyde found to be tough,flexible and resistant to abrasion.

Example XV Grams Ethyl cellulose (viscosity 300 centipoises) 12 Orthonitro diphenyl. 20 Ester gum v I 20 Hydrogenated castor oil 6 resin weremelted in an oil-jacketed mixer at a.

temperature of 130 C. The ethyl cellulose was added and the temperaturewas raised to 160 C. over a period of 30 minutes and maintained at thattemperature for 20' minutes. Thereupon the reaction mixture was cooledto 130 C The xylene and fatty acids were added quickly. Mixing wascontinued for 10 minutes to give an homogeneous solution at atemperature of about to C. The solution was then agitated rapidly untilemulsification had taken place. Agitation was continued for anadditional 20 minutes. The product thus formed was a very thick emulsionof lowsolids content. When applied to a surface of paper, wood, leatheror metal, it formed a dull, white, opaque film which,

or the elastomer compositions of this invention is prepared according tothe following formula:

. Liters Denatured alcohol (containing gasoline and ethyl acetate)xylene 20 Benzene 15 Rubber solvent (initial boiling point 100 F.

end point 260 F.) 35

The usual rate of dilution of the elastomer or the elastomer compositionis 2% pounds of solid per gallon of solution. This may be increased toas much as 4 pounds per gallon or more. Elasg a,asa,c1s' tomerdispersions thus prepared have been folmd I vention with syntheticrubber, such as neoprene rubber or butadiene rubber, it is desirable toemploy a small quantity of a solvent for the elastomer initially toaccelerate the dispersion of the elastomer in the synthetic rubber. Inthis manner, from 6% to 75% or more of the elastomer,

based on the synthetic rubber, may be used to extend the syntheticrubber and thereby to lower the cost of the product without detractingfrom the useful characteristics of the synthetic rubber. Elastomers,which have beenextended by incorporation of auxiliary resins, such asrosin-81y?- erine resin (ester gum), phenol-aldehyde resins andisomerized terpene resins are desirably employed as extenders forsynthetic rubbers.

In the manufacture of rubbery articles, such as gaskets and washers,embodying the elastomers of this invention, it is desirable to prepare a50% solution of the elastomer inxylene and to pour the hot solution intoappropriate molds. The cast solution is allowed to air-dry for 25 hoursor more to expel the solvent and to form a rubbery solid. The xylene isdesirablydncorporated with the reactants after a melt has beenestablished.

In the manufacture of a tougher variety of article, such as washers andgaskets for application to acid, hot water or hot oil fittings, it isdesirable to cast a hot melt of the elastomer in molds and thereafter toreduce the thermal plasticity of the molded article by vulcanizationwith sulfur or by incorporating an additional quantity of a hard resinsuch as an aryl sulfonamidealdehyde resin.

Within relatively wide limits, the temperature at which the reaction isconducted in the preparation of the elastomers of the present inventionappears to have little influence on the characteristics of the finalproduct, except, in some instances, at higher temperatures a somewhatdarker. harder and tougher product is produced. The duration of theheating period appears to have a definite but minor influence in thesame direction.

The novel elastomers of this invention possess great utility in theiield of rubber substitutes for many purposes. For example, theelastomers may be used with success in the manufacture of gaskets,washers, acid-resistant tank linings, roofing compositions, vibrationdampers, conveyor belt linings, flooring, chute linings and otherarticles for which a tough rubbery a rasion-resistantmaterial isdesired. Coating emulsions embodying these elastomers are particularlyuseful in manufacturing acid-proof clothing, imparting corrosion andabrasion resistance to sheet metal, metallic and non-metallic particlesand improving the impermeability of cloth for balloons and otherpurposes for which a rubber abrasion and substantially from theinvention which is defined in the appended claims. I

I claim 1. An elastomer comprising the product of the 5 thermal reactionof water-insoluble ethyl cellulose, at least one normally solid,crystalline substituted polyphenyl hydrocarbon selected from;

the gr up consisting of ortho nitro-dlphenyl, ortho, meta and paradiphenyl benzenes and mixtures of said substituted hydrocarbons; and ahydrogenated higher fatty acid glyceride; said materials, with theexception of ethyl cellulose, being formed into a hot melt, said ethylcellulose being incorporated therein and said melt thereupon l5 heatedat a temperature between 140-240" C. for

a-period of time ranging from minutes to 4 hours.

2. A coating emulsion comprising, in one phase,

20 formed by the thermal reaction of water-insoluble ethyl cellulose, atleast one normally solid, crystalline substituted polyphenyl hydrocarbonselected from the diphenyl, ortho, meta and para diphenyl benzenes andmixtures of said substituted hydrocarbons; and a hydrogenated higherfatty acid glyceride; and in the other phase, an alkaline-emulsifyingagent dissolved in water; said hydrocarbons being formed into a hotmelt, said ethyl cellulose being so incorporated therein and said meltthereupon heated at a temperature between 140-340" C. for

a period of time ranging from 20 minutes to 4 hours, after which saidthermal reaction product is cooled to normal temperature.

3. An elastomer composition comprising the product of the thermalreaction of one part by I weight of water-insoluble ethyl cellulosehaving a viscosity of 100-300 centipoises; 0.4-2 parts by weight of atleast one normally solid, crystalline 4o substituted polyphenylhydrocarbon selected from the group consisting of ortho nitro diphenyl,ortho, meta and para diphenyl benzenes and mixtures of said substitutedhydrocarbons; and 0.1- 1.0 parts by weight of a hydrogenated higherfatty acid glyceride; said hydrocarbons and higher fatty acid glycerideformed into a. hot melt into which said ethyl cellulose is incorporatedand the temperature maintained thereafter between 140 --240 C. for aperiod of time ranging from 20 minutes to 4 hours, after which saidthermal reaction product is cooled to normal temperature.

4. A coating emulsion comprising, as one phase, from 5% to 20% of anacidic emulsifying agent and an elastomer composition, which compositionis the thermal reaction product of one part by weight of water-insolubleethyl cellulose having a viscosityof 100-300 centipoises; 0.4-2 parts byweight oi at least one normally solid, crystalline substitutedpolyphenyl hydrocarbon selected from the group consisting of ortho nitrodiphenyl, ortho, meta and para diphenyl benzenes and mixtures of saidsubstituted hydrocarbons; and 0.1- 1.0 parts by weight of a hydrogenatedhigher fatty acid glyceride; said hydrocarbon and higher fatty acidglyceride formed into a, hot melt into which said ethyl cellulose isincorporated and the temperature maintained thereafter between 140-240C. for a period of time ranging from 20 minutes to 4 hours, after whichsaid thermal 70 reaction product is cooled to normal temperature.

5. The process of making an elastomer composition which comprisesforming a hot' melt consisting of 0.4-2.0 parts by weight of at leastone normally solid, crystalline substituted polyphenyl 7g hydrocarbonselected from the group consistin an acid-emulsifying ag nt and anelastomer group consisting of ortho nitro- 6 a a,ses,o1a

of ortho nitro diphenyl, ortho, meta and para diphenyl benzenes andmixtures of said substituted hydrocarbons; and 0.1-1.0 parts by weightof a hydrogenated fatty acid glyceride: incorporating into said melt onepart by weight of water-insoluble ethyl cellulose having a viscosity inthe range of 100-300 centipoises, heating said melt to a temperature inthe range of 140-24,0 C. for a time within the range of 25 minutes to 4hours and subsequently cooling said melt. v

6. A coating composition comprising a normally liquid aromatichydrocarbon dispersion of an elastomer composition comprising theproduct of the thermal reaction of water-insoluble ethyl cel-r lulose,at least one normally solid, crystallinesubstituted polyphenyihydrocarbon selected from the group consisting of ortho nitro diphenyl,ortho, meta and para diphenyl benzenes and mixtures of said substitutedhydrocarbons; and a hydrogenated higher fatty acid glyceride; saidhydrocarbons and higher fatty acid glyceride formed into a hot melt intowhich said ethyl cellulose is incorporated and the tempera-tinemaintained thereafter between 140-240 C. for

a period of time ranging from 20 minutes to 4 hours, after which saidthermal reaction produ is cooled to normal temperature. 1

7. A coating composition comprising a normally liquid aromatichydrocarbon dispersion of an elastomer composition comprising theproduct of the thermal reaction of one part by weight of water-insolubleethyl cellulose having a viscosity of 100-300 centipoises; 0.4-2 partsby weight of at least one normally solid, crystalline substitutedpolyphenyl hydrocarbon selected from the group consisting of ortho nitrodiphenyl, ortho, meta and para diphenyl benzenes and mixtures of saidsubstituted hydrocarbons; and 0.1- 1.0 parts by weight of a hydrogenatedhigher fatty acid glyceride; said hydrocarbons and higher fatty acidglyceride formed into a hot melt into which said ethyl cellulose isincorporated and th temperature maintained thereafter between 140-240 C.for a period of time ranging from 20 minutes to 4 hours, after whichsaid thermal reaction product is cooled to normal temperature.

HARRY KELLER.

